Cutting and milling tool and method of manufacturing the same



Patented May 12, 1925.

UNITED STATES PATENT.

OFFICE.

ammo STRAUSS, "or' ESSEN, GERMANY, ASSIGNOR To FRIED. KRUPP AKTIENGE- I 'SELLSCHAFT,' or nssnn-on-rnn-ncnn, GERMANY.

CUTTING AND MILLING" TOOL METHOD OF IANUFACTURING THE SAME.

No Drawing.

Application filed December 28, 1920. Seriallio. 438,851.

I (GRANTED UNDEi. THE PROVISIONS OF THE ACT 01' LIARGH 3, 192 1, 4 1 STAT. I, 1313.) I

To all whom it may ogmccm:

Be it known that I, Dr. BENNO STRAUSS, residing at Essen, Germany, a citizen of the German Republic, have invented a certain new and useful Improvement in Cutting and, Milling Tools and Methods of Manufacturing the Same (for which I' filed application in Germany March 28,1919), of which the following is a specification.

This invention relates to an improved method of manufacturing cutting and millhigh efficiency.

, tempering process by first heating and then ing tools, remarkable for their particularly The method consists in making the said tools of an alloy of ironnot capable of being hardened per secomprising from 0.1

to 0.2% 10f carbon and 8 to 14% of chromium, then cementing them at the cutting edge in the customary manner, and finally subjecting the tools so made to the usual quenching them.

(It has been found expedient to add nic el to the alloy in a proportion offroni 0.2 to 2%).

.In the case of tools manufactured in ac+ cordancewith the above-described method, it is only the cemented cutting edge which becomes glass-hardened whereas the adjoining layers of the steel obtain a gradually decreasing degree of hardness and great toughness, witi the result that the cutting edge will be rendered specially capable of achieved on the entire tool heated and then quenched as an entiret taking up the shocks created when working, without breaking 'off or snapping. This advantage will particularly also then be eing uniformly The improved method is therefore specia y suitable for such kinds of tools which, as, for example, milling cutters and face and side cutters, can only be hardened, by-being uniformly heated and thereupon quenched as entirety. For, in this case, tools of this type if made of common tool steel or of high speed tool steel, would not only become glass-hardened at the cutting edges but in an objectionable manner all over.

Furthermore, owin to the fact that in the case of tools ma e in accordance with this improved method, layers of steel of less hardness adjoin the glass-hardened cuttingedge, there is attained the advantage that the material, which becomes detached in the cutting operation, .will gradually make a recess in the softer layers of steel disposed to the rear of the cutting-edge by exerting a grinding action thereon, and thus automatically serving to produce a favourable sha ing of the cuttin angle. This feature wilFbe found to be 0 great importance for profile tools, the cutting edges of which can either not be backed off at all or only by the V kilogs on employing a high speedcuttingtool, and 210 kilo on employing a tool made in accordance w1th the present process. It will thus be seen that the efliciencies resulting are as 1:2:162. ,Attention may be directed in this connection to the feature'that in the case of the tool made in accordance with the invention, the cutting depth was cutting amounted to 13 kilogs tools grew blunt amounted to 4.2 kilogs in I the case of a tool "made ofwordinary toolsteel, and 175 kilogs in the case of a tool madein accordance with the invention, this correspondin to a proportion of 1:41].

In thls particular case, the conditions" as regards cutting speed, cutting depth and feed action were completely 1 entical.

. Taking the average, as a result of nufound that tools made in accordance with merous tests of a similar kind made, it was the described method possessed a twenty fold superiority over tools made of c'onnncn-v -toolsteel.

'I claimp being-hardened perse, which consists in 3. Acutt ing or milling tool maide of any treating and alloy'of steel comprising 0.1m

0.2% of carbcn and 8 to 14:% of chromium by a. ceinenting rocess at the cutting edgesand then subjecting the tcols to the customary tempering process.

2. A method zis'described in claim 1 with of. nickel .to an f the .addition to the 8 110 extent of from 0.5 to 2.0

alln'y of steel' comprising her, 1920.

Lumps-1 giliq yhf steel comprising 0.1 to of car b'on and 8 to 14% of chromium with -its cutting edges hardened b 'a'cementing process. .4. A cutting .or mi ling tool made of an 7 0.1 to 0.2% of carto'l4%'of chronnum and 0.5 tc. 2.0%

0 f.nicke1 with its cutting edges hardened by elcementing process. p 1 y-The foregoing specification signed at Essen, Germany, th1s 15th day of Noveln- DR. 'BE NO STRAUSS. Iii-presence 0f I HANS Go'rrs nmn, JOHANN DECKERS. 

